BLOOD ON THE STEP (III)

In previous articles on this subject, we came to the provisional conclusion that Nicole's throat was slashed while it was over the middle of the blood pool on the first step. We were led to this because the lack of a great splatter pattern anywhere in the crime scene and the distribution of blood on the bottom of her nose and up into her nostrils indicates that her throat was slashed close (within 6 inches) to the surface over which the initial throat wound bled. And, since fluid does not flow uphill (as from the walk to the step) only bizarre scenarios account for the blood on the step in this case if the great wound did not occur over the step. We also believe that Nicole was face down with the killer behind her during the throat slashing, since any other orientations would produce a great amount of her blood on the killer, a conclusion that is particularly contrary with the "too little blood in the Bronco" observation. In this article we continue to explore the significance of indications about blood on the first step.

MORPHOLOGICAL CONSIDERATIONS: The size and location of physical objects in the crime scene, particularly the steps, and the size, shape, and range of movement of Nicole's body parts limit the possibilities somewhat. I have a concrete front porch with concrete steps leading to it; when I measure these I find that the tread is 12 inches wide and the riser is 8 inches high. I have assumed that the steps at Nicole's front walk are of the same dimensions. Nicole was a woman of standard body proportions and was 5'5" tall. I have a friend who is 5'4" tall and of standard proportions, and I measured from her that from the top of the head down to 12" (equivalent to the step width) brings one to the collar bone. The location of the slash to Nicole's throat is about 3" above this, meaning that it was about 9" from the top of her head.

In Figure 14 I have posed a female of standard proportions kneeling with her head over thefigure14.jpg (17255 bytes) step. If the top of her head is in contact with the second riser and the nose is touching the first step, then the slash is 3" from the edge of the step and is 4" above the step. This would produce indications of no splatter, and heavy blood deposits on the front of the face seen in the crime scene.

A kneeling position for the victim is ideal from the killer's standpoint; it is a compact configuration (as opposed to a posture of victim lying on her stomach) and is easy to control, although it does take a few seconds to arrange. It is also a practical posture for the restricted size of the crime scene. Finally, it is ideal if the objective is to deposit blood on the step, since the head is naturally in a position that favors a compact and deep pool. For these reasons, I have assumed a kneeling posture for the victim, though I realize that the alternative (victim lying prostrate, face down) is also possible.

VICTIM LOCATIONS: In order for Nicole's throat to have been within 6 inches of the surface over which it was slashed, she had to have been in a posture near to the ground, either prostrate, face down, or kneeling. The first of these is a posture that occupies much space, and as has often been noted, the quarters at the site of the crime were rather confined. If she were in a prone position, it could not have been with her head to the north or south, because her 5'5" length is greater than the 4 foot width of the place. If it was prone with the head to the east, then her body and legs would have been reaching up the steps with her throat over any of the major blood deposits. While not impossible, it is an awkward position for the killer, and implies his considerable deliberate movement of the body after the throat slashing. Of all the prone positions, only the one with the head toward the west (within 15 or so degrees) seems plausible. It allows the killer a reasonable freedom of action, but still requires that the body be repositioned to a kneeling position, laying on its side at the end. These do not seem to be changes that could be accounted for by "death spasms" alone, if the victim were lying on her stomach facing west when her throat were slashed.

This then leaves throat slashing postures in which the victim is kneeling at the time. Although this fact itself seems contrary to Simpson as killer (why would he compose Nicole in a particular way to slash her throat?) it must be admitted that when she "fell in a heap" after her carotid artery was punctured, the "heap" could have been more or less a kneeling position. So, the fact that her throat was slashed while she was in such a position does not necessarily imply that she was deliberately composed into that position.

In Figure 15, I show the arrangement if Nicole is kneeling with head to the south (Figure 15A), figure15.jpg (21084 bytes)west (15B) or north (15C). A posture kneeling facing east puts all of the major blood deposits uphill from the throat, and was not considered. With Nicole kneeling in the north or south orientations, her body takes up 37 inches in a 48 inch space, leaving only a range of 11 inches for the position of the throat. All of these positions for the south orientation are over regions in which there was no significant blood found, so we conclude that she was not kneeling facing south. The west position allows for the throat over the blood pool on the step, and the north orientation allows for the throat to be over the part of the blood pool that was eventually behind Nicole's shoulder. Thus, either the north or the west orientations are possible without requiring that blood would be shed in areas where no blood was found.

However, no matter which of these orientations was the fact, some movement of the body after the throat was slashed occurred to account for the distribution of blood in other areas. If the slashing occurred with the body pointed north, then it must have been moved over the step to account for the blood there, then later been moved to the final resting position. If the slashing occurred with the head to the west, then one movement (east a few inches for the gash to clear the edge of the step, then ninety degrees clockwise) to the final position is required. It is, by far, simplest to believe that Nicole's throat was slashed over the step while she was kneeling with her head to the west.

PRESSURE: I have seen comments both in the newsgroup (Robert Seigler) and in my e-mail, that the flow rate from a slit throat can not be studied by pouring liquid on a hard surface. The argument is that because the cardiovascular system is under pressure, and the fluid is flowing in a duct, the effect can only be simulated by using some high pressure method of spraying the liquid. Seigler proposes a paint sprayer; my e-mail tells me of experiments done by attaching a spray nozzle to the kitchen sink.

Both of these methods produce pressures in the 60 to 150 pound/square inch (psi) range. It is a familiar fact to most people that the pressure of the human cardiovascular system is nominally 100 millimeters of mercury (mm of Hg.), though under stress it can go to twice this level, or more. What is not usually realized is how that pressure relates to more ordinary measurements. 100 mm of Hg. is equivalent to 4.5 feet of water, or about 2 psi. That is, the pressure at the bottom of a column of mercury 100 mm tall (3.94 inches) is the same as the pressure at the bottom of a column of water 4.47 feet tall, and that pressure is 1.93 psi. Obviously, methods of study that employ pressures more than 30 times as great as actually found in the human system would not yield relevant information.

(From the foregoing considerations we can now understand Dr. Spitz' comment in the civil trial, that a wound like Nicole's was a "pulsating hemorrhage that would go up to a twelve foot ceiling." This requires a seven foot vertical jet from a wound five feet off the ground for an erect person. A seven foot jet requires 7/4.47 times the pressure described in the previous paragraph for the nominal blood pressure. That is, Spitz' twelve foot ceiling requires that the blood pressure in the victim be 155 mm of Hg, which is not at all improbable under the circumstances of being murdered. So, Dr. Spitz' comment should be taken as a theoretical consequence of throat slitting. He himself disclaimed the relevance of the "twelve foot" comment to Nicole's murder later in his testimony, and we will see below that because the head is in the way of these jets, they could not actually project farther than the jaw line unless the victim were decapitated, and the head removed; not the case here.)

NATURE OF THE OPENING: A nozzle (as used in another author's study) is a mechanical device for converting fluid pressure into velocity in that medium. Its opposite is a "diffuser" which slows down a moving fluid to a lower velocity. Typically, a nozzle is a region of progressively constricting cross section to the flowing stream, a diffuser is a region of progressively dilating cross section. Which of these simulates the situation in the slit throat? To produce a nozzle effect, the killer would have to reach into the gushing wound, locate the artery walls by feel, and pinch them partly shut. I am sure we can believe this did not happen. This leaves us with two possibilities, depending on the condition of the neck at the time the wound was administered. If the throat were extended, as by pulling back on the victim's hair, there would be neither a constriction nor a dilation of the flow before it escaped into the air. If the neck were compressed, as by pushing the head down toward the chest, there would be the effect of a diffuser, since the blood emerging from the artery encounters progressively wider spaces as it traverses the wound, eventually emerging by flowing through a channel with a greater cross section than the artery itself. If this happened, the blood would gush out of the throat wound at relatively low velocity.

However, with the victim's head down it is also possible to pinch, or close up the wound after the knife passes. In this event, the result is not a diffuser, and may actually function slightly like a nozzle. So, the head down position is by itself ambiguous. Depending on the exact forces the killer put on the head, the velocity in the emerging flow might be either slightly greater or less than the velocity within the artery.

HEAD PULLED BACK? Dr. Lakshmanan believed (and, as a result of this study, I now disbelieve) that Nicole's head was pulled back by the killer, using and handful of hair in his left hand, to extend the throat. I show in Figures 16 and 17 a cartoon of a woman's head in which the head isfigure16.jpg (23775 bytes) bowed to rest on the step (Figure 16) and pulled back as Dr. Lakshamanan thought (Figure 17). (The hair has been removed so as not to obscure the neck.) The carotid arteries are shown in blue and the wound is shown in black. I have attempted to show the arteries as 3/4" diameter after Dr. Spitz's description, "the size of your little finger."

figure17.jpg (22910 bytes)From Figure 16 we see that if the head was bowed forward when the throat was slashed, the structures there are in a state of compression, and will tend to close up as the knife passes. The blood, under pressure, will escape nonetheless, but will more flood out that spurt out. The head blocks the anterior flow, and there is nowhere for the blood to go but down to the step, or possibly to the side. In Figure 17, however, with the neck pulled back, the structures of the neck are in tension, and when the knife parts those structures, they will come apart at the incision, leaving a wide, gaping wound. The head is less effective in blocking forward flow, and it would be expected that either the main gush or the first ricochet would reach the second riser and leave blood stains part way up that. In fact, a photograph of the second riser shows that there is only a small amount of blood -- within half an inch of the step -- there. Also, the previously mentioned indications of blood on the bottom of Nicole's nose and up in her nostrils are inconsistent with the blood flow pattern that would result if her head were pulled back.

So, the compact size of the blood pool on the step and the absence of splash on the second riser indicate that the neck was not pulled back when the throat was slashed. When Dr. Lakshmanan expressed a contrary view, I think he was relying on the fact that 36 of Nicole's head hairs -- forcibly broken -- were conveyed to Ron Goldman's body. It is natural to think that these got on the killer's left hand while he had hold of Nicole's hair and applied considerable force to it. I think that too. But, from the forgoing, it does not appear that this force was applied to extend her throat. And we would have doubted this on the basis of the number of hairs broken. It only takes five or ten pounds to pull back the head and extend the throat, but such a small force would not cause the breakage of so many hairs.

I think that a more likely explanation for the broken hairs is that the killer used a handful of Nicole's hair as a handle by which to move the upper part of her body after the throat was slashed, and turn her into the head-to-the-north position in which she was found. This maneuver would require the application of 60 or 70 pounds, and would be more consistent with the number of hairs broken. Also, it is now rather well established now that the throat was slashed over the first step, and the body moved to the somewhat different orientation in which it was found. If this movement was by the hand of the killer, the hair would be a natural place to apply the forces for the top part of the body.

FLOW RATES:
Since posting my flawed analysis of the finite spreading rate of the blood pool, I have received many inputs concerning the nature of the flow from a slit throat. Some of these are valuable, some are not. But, they have all influenced my present understanding of the phenomenon. I have summarized this in Figure 18, figure18.jpg (33623 bytes)in which I show roughly the time behavior of the flow rate, as I understand it. Every account by people who have seen the results of a slashed throat agrees that there is an initial gush in the first few seconds, and it produces a remarkable amount of blood. I have tried to get a reliable figure for the quantity in this spurt, but have not succeeded.

I am advised that my earlier estimate of 2 pints in four seconds requires more than three times the maximum cardiac capacity. However, I consider that some abnormal mechanism may be at work in the initial stage of this process. All firsthand accounts report that this initial gush abates in 10 seconds or so to a rate that is sustained for a longer period -- until the victim dies. I take this as an indication that what is seen after 10 seconds is the result of the normal cardiac output, and before 10 seconds this is augmented by some other mechanism. I have conjectured that this other mechanism derives from the fact that the cardiovascular system is an elastic structure under some pressure before the wound occurs, and that the relaxation of this elastic tension produces a brief abnormal flow. But, this is frankly a guess; all I feel confident about is that there exists some brief abnormal flow.

From the reports I have found, I believe that this initial gush produces a pint of blood in three to five seconds, and produces a total of 2 pints in about the first ten seconds. Following that, blood is expelled at a rate roughly comparable to the normal cardiac capacity until the total volume falls to about 40% of the initial volume, the victim dies, and the heart stops. If the wound is lower than the level of the blood remaining in the body, blood will continue to escape through the simple method of hydrostatic draining.

BLOOD ON THE RISER:
In Figure 19 I have reproduced a picture from Court TV of the blood on the first riser. Notice the following:figure19.jpg (19182 bytes)

1) The blood flowed off the step in a wide (18 inches) front. We have already interpreted that as showing that a great flow rate occurred on the step which is only consistent with the fact that Nicole's throat was slashed while it was over that step.

2) There is very little blood reaching from the step up the second riser -- less than half an inch -- and no splatter on the second riser. We have interpreted that this is one of several indications that Nicole's head was not pulled back, extending her neck, while her throat was slashed.

3) There occur several indications of partial flow down the riser. These are on the left, where the stain reaches only about two thirds the way down the riser before there is a wedge-shaped area devoid of blood. Another indication occurs on the right side of the main flow where there is a less pronounced concavity in which there is no blood. Finally, there are two rivulets of blood on the far right. All of these cases indicate situations in which blood was shed locally, in limited amount, and ran over the edge before it was connected to the main flood and its wide spill down the riser, which would provide an easier path for draining.

Consider the situation on the left, for example. At some instant before blood had begun to flow down the main cascade, there was blood near the edge of the step that began to spread out, and encountered the edge and began to flow down. By the time it got about half way down the riser one of two things happened: either the pool feeding this descending stream was exhausted, or it became connected with the main pool, which by then had an easier egress over the edge in a wide front. We can visualize that since the knife stroke that slit Nicole's throat began on the left side, the very first blood that was produced came in a spray on the left side. This would produce a little pool on the left which was not yet connected to the main pool, and as it spread out, it began to spill down the riser. Before it got more than a few inches, though, the knife had progressed farther, the blood on the step was more general, and any further draining occurred via the main pool and its cascade. A similar but less pronounced indication on the right could be the result where the right carotid spurted out to the right side of the neck.

The two dribbles at the extreme right side of the riser may be from different sources. The one to the right may be overflow from a small puddle which arose from blood shed from the perforated carotid artery. The left hand dribble could be from a small puddle splashed up when the Bruno Magli shoe stepped into the right side of the pool on the step.

The situation is also shown in a TV news picture I show here as Figure 20. figure20.jpg (28004 bytes) In that view some splatter in the bottom edge where the second riser meets the first step is evident.  This implies that there was a horizontal (westward) component of some slight force to the blood flow when it was deposited on the step.  This is consistent with the previously developed idea that Nicole's head was pointed west, close over the first step, when her throat was slashed.  Although the direct carotid jets were caught by her chin and diffused, there still remained some forward velocity that resulted in this splashing at the end of the step.


CONCLUSION: The most likely interpretation of the configuration of the blood pools at the crime scene is that:

1) Nicole's throat was slashed while she was on her knees, facing west, with her head over the first step and her nose against it. She was probably unconscious at this time from the perforation to her carotid artery, and when she became unconscious probably fell to the steps face up, causing the bruise to the back of her head.

2) Immediately after making the two slashes across her throat, the killer set his knife on the second step and then, using the hair on her head as a handle, moved Nicole east a couple of inches, then swung the top of her body clockwise, with the head to the north, and finally rolled her onto her left side.

3) The killer then forced Nicole's feet and right leg under the fence, jamming them in there so hard that he abraded the skin from those areas. This could have been done to prevent death spasms from further repositioning her body.

4) The killer reclaimed his knife from the second step, banging it several times there to get the loose blood off it, and finally shook it again over Nicole's shoulder.

5) Some time later, when the pool on the first step had somewhat congealed, and was no longer flowing completely free, someone stepped into its right side, causing a thinning to the pool and an irregularity to its edge that could not be naturally erased by the redistribution of the drying blood.

This sequence conforms exactly to the blood indications on the first step and around Nicole's body. No alternative considered here explains the facts as well.

Dick Wagner • Van Nuys, CA (3/26/99) NG_534

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